1. Field of the Invention
The present invention is generally related to a heat adhesive bicomponent fiber, and more particularly to a heat adhesive biodegradable bicomponent fiber.
2. Description of the Prior Art
Heat adhesive bicomponent fibers have been extensively applied in the field of synthetic fibers, such as polyester, polyamide and polyolefin fibers. These fibers are mostly used in nonwoven processes, especially in disposable nonwoven fabrics that thereby results in waste disposal problem.
For example, disposable diaper comprises an absorbent layer that comprises a water permeable surface layer, a water impermeable rear layer, and a single-layer or multi-layer structure for liquid dispersion wherein the material of the absorbent layer generally comprises natural fiber, such as cellulose fluff pulp fiber, and polyolefin and/or polyester based synthetic fibers and super absorbent polymer (SAP) substance. The synthetic fibers generally are polypropylene/polyethylene or polyester/polyethylene bicomponent fibers that are heat treated to adhere to each other to form a supporting web structure. In an ideal situation, the bicomponent synthetic fibers bond together and also bond with natural fibers and the super absorbent polymers to form the above described supporting web structure.
In addition, nonwoven fabrics manufactured by a spunlace nonwoven fabric process are extensively used in the products of wiping fabrics. These products usually use rayon as the main body and add bicomponent polyester low melting bicomponent fibers or add bicomponent polyolefin fibers or polyester fibers and thereby increase the physical property of the nonwoven fabrics by heat bonding process.
However, the products made by either polypropylene/polyethylene or polyester/polyethylene bicomponent fibers are not biodegradable after disposal and thus pollute the environment. Therefore, developing a biodegradable and heat adhesive fiber is an important subject as well as an important research aspect for the industry.